core: add file missing from previous checkin (serirq.inc)syslinux-3.81-pre11

Add the file serirq.inc missing from previous checkin.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 184 insertions, 0 deletions

diff --git a/core/serirq.inc b/core/serirq.inc
new file mode 100644
index 00000000..8b04728a
--- /dev/null
+++ b/core/serirq.inc
@@ -0,0 +1,184 @@
+;; -----------------------------------------------------------------------
+;;
+;;   Copyright 2009 Intel Corporation; author: H. Peter Anvin
+;;
+;;   This program is free software; you can redistribute it and/or modify
+;;   it under the terms of the GNU General Public License as published by
+;;   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
+;;   Boston MA 02111-1307, USA; either version 2 of the License, or
+;;   (at your option) any later version; incorporated herein by reference.
+;;
+;; -----------------------------------------------------------------------
+
+;;
+;; serirq.inc
+;;
+;; Serial port IRQ code
+;;
+;; We don't know what IRQ, if any, we have, so map all of them...
+;;
+
+		section .text
+		bits 16
+		align 8
+
+		section .bss
+		alignb 8
+
+%assign n 0
+%rep 16
+		section .text
+serstub_irq %+ n :
+		push dword [cs:oldirq %+ n]
+		jmp short irq_common
+
+		section .bss
+oldirq %+ n	resd 1
+%assign n n+1
+%endrep
+
+		section .text
+irq_common:
+		pushf
+		push ax
+		push dx
+		mov dx,[cs:SerialPort]
+		add dx,5			; DX -> LSR
+		in al,dx
+		test al,1			; Received data
+		jnz .data
+.done:
+		pop dx
+		pop ax
+		popf
+		retf				; Chain to next handler
+.data:
+		push es
+		push di
+		mov ax,aux_seg + (aux.serial >> 4)
+		mov es,ax
+		mov di,[cs:SerialHead]
+.loop:
+		mov dx,[cs:SerialPort]		; DX -> RDR
+		in al,dx
+		stosb
+		mov ah,[cs:FlowIgnore]
+		add dx,5			; DX -> LSR
+		in al,dx
+		push ax
+		and al,ah
+		cmp al,ah
+		jne .drop
+		and di,serial_buf_size-1	; Wrap around if necessary
+		cmp di,[cs:SerialTail]		; Would this cause overflow?
+		je .drop			; If so, just drop the data
+		mov [cs:SerialHead],di
+.drop:
+		pop ax
+		test al,1			; More data?
+		jnz .loop
+.full:
+		pop di
+		pop es
+		jmp .done
+
+		section .data
+;
+; SerialIRQPort will generally track SerialPort, but will be 0 when an
+; IRQ service is not installed.
+;
+SerialIRQPort	dw 0			; Serial port w IRQ service
+SerialHead	dw 0			; Head of serial port rx buffer
+SerialTail	dw 0			; Tail of serial port rx buffer
+
+sirq_install:
+		pushad
+
+		call sirq_cleanup
+
+		; Save the old interrupt vectors
+		mov si,4*08h
+		mov di,oldirq0
+		mov cx,8
+		rep movsd
+		mov si,4*70h
+		mov cx,8
+		rep movsd
+
+		; Install new interrupt vectors
+		mov di,4*08h
+		mov cx,8
+		mov eax,serstub_irq0
+.pic0:
+		stosd
+		add ax,serstub_irq1 - serstub_irq0
+		loop .pic0
+		mov di,4*70h
+		mov cx,8
+.pic1:
+		stosd
+		add ax,serstub_irq1 - serstub_irq0
+		loop .pic1
+
+		mov bx,[SerialPort]
+		mov [SerialIRQPort],bx
+
+		lea dx,[bx+5]		; DX -> LCR
+		in al,dx
+		and al,7Fh		; Clear DLAB (should already be...)
+		slow_out dx,al
+
+		lea dx,[bx+1]		; DX -> IER
+		mov al,1		; Enable receive interrupt
+		slow_out dx,al
+
+		popad
+		ret
+
+sirq_cleanup:
+		pushad
+		push ds
+		push es
+		xor ax,ax
+		mov ds,ax
+		mov es,ax
+
+		mov bx,[SerialIRQPort]
+		and bx,bx
+		jz .done
+
+		lea dx,[bx+5]		; DX -> LCR
+		in al,dx
+		and al,7Fh		; Clear DLAB (should already be...)
+		slow_out dx,al
+
+		lea dx,[bx+1]		; DX -> IER
+		xor ax,ax
+		slow_out dx,al		; Clear IER
+
+		; Restore the original interrupt vectors
+		mov si,oldirq0
+		mov di,4*08h
+		mov cx,8
+		rep movsd
+		mov di,4*70h
+		mov cx,8
+		rep movsd
+
+		; Just in case it might contain a password, erase the
+		; serial port receive buffer...
+		mov [SerialIRQPort],ax
+		mov [SerialHead],eax
+		mov cx,aux_seg + (aux.serial >> 4)
+		mov es,cx
+		mov cx,serial_buf_size >> 2
+		xor di,di
+		rep stosd
+
+.done:
+		pop es
+		pop ds
+		popad
+		ret
+
+		section .text